"In a move that has raised eyebrows, Microsoft has submitted a patch to the WebKit project to extend the open source rendering engine with a prototype implementation of the Pointer Events specification that the company is also working on together with Google, Mozilla, and Opera. WebKit is the rendering engine used in Apple's Safari and Google's Chrome browsers, making Microsoft's work a contribution to products that are in direct competition to its own."

Without getting too specific, there are several extensions that are specific to Apple's browsers that cover things like drawing a beveled edge on an element. Nothing really groundbreaking. Google has their own in Chrome that cover much of the same stuff, and Mozilla has their own in Gecko that cover much the same stuff. Frequently the only difference is the syntax.

These extensions exist generally because they're new features, and the HTML spec hasn't standardized on the specific implementation. However, these aren't meant to be used on production web pages. The problem arises when a site uses them on public-facing pages, and is even worse when they don't put the time in to degrade gracefully, so they tell users that they either "need to upgrade to HTML5" or they just serve a broken page.

Web designers seem to tend to do this more with Safari extensions, but that's merely anecdotal observation on my part.

But, Google did it in a big way with their super-frickin-awesome WebGL star map with WebGL detection code that seemed to not work on my Firefox install.

Apple's extensions to provide touch interactions within HTML5 is troublesome, especially in light of the fact that they refuse to work with the W3C to standardize what they have (because it involves royalty free use, presumably) and they refuse to get behind Microsoft's Touch efforts.

The amount of the mobile web that uses proprietary prefixed touch extensions is scary. It isn't a mobile web, it's a WebKit web, and other vendors namely Mozilla, Opera, and Microsoft are left out in the cold.

It is very convenient for Apple to lock-in the mobile web using their touch model, (and more, a lot of the mobile web also uses prefixed CSS transitions and text scaling properties specific to WebKit)

Google by virtue of using WebKit gets these things for free, but other vendors don't. That's what is fundamentally broken about Apple's approach.

If you think being a Web Dev is hard, try doing Mobile Web development. A complete nightmare.